ALDASHEV, S. A. Criterion for the uniqueness of a solution of the Darboux-Protter problem for multidimensional Hyperbolic equations with Chaplygin operator. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 56, n. 8, p. 1119–1127, 2004. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/3826. Acesso em: 6 dec. 2025.